From the ArcaMax Publishing, Vocabulary Newsletter:
http://www.arcamax.com/news/vocabulary/s-355796-806538
acrid \AK-rid\ (adjective) - 1 : Sharp and harsh, or bitter to the
taste or smell; pungent. 2 : Caustic in language or tone; bitter.
"It sizzled and sparked, and sent its acrid odor up everyone's
nostrils; Jennifer thought of hellfire." -- Richard Janssen, 'The Evil
I Do'
Acrid comes from Latin acer, "sharp."